Epithelial cancer cells often have unusually higher mitochondrial membrane potential (ΔΨm) than their normal counterparts, which has been associated with increased invasiveness in vitro and higher metastatic potential in vivo. However, the mechanisms by which ΔΨm in cancer cells is regulated in tumor microenvironment (TME) remain unclear. In this study, we used an in vitro micropatterning platform to recapitulate biophysical confinement cues in the TME and investigated the mechanisms by which these regulate cancer cell ΔΨm. We found that micropatterning resulted in a spatial distribution of ΔΨm, which correlated with the level of E-cadherin mediated intercellular adhesion. There was a stark contrast in the spatial distribution of ΔΨm in the micropattern of E-cadherin-negative breast cancer cells (MDA-MB-231) compared to that of the high E-cadherin expressing (MCF-7) cancer cells. Disruption and knockout of E-cadherin adhesions rescued the low ΔΨm found at the center of MCF-7 micropatterns with high E-cadherin expression, while E-cadherin overexpression in MDA-MB-231 and MCF-7 cells lowered their ΔΨm at the micropattern center. These results show that E-cadherin plays an important role in regulating the ΔΨm of cancer cells in the context of biophysical cues in TME.
Keywords: CRISPR/Cas9; E-cadherin; MCF-7; MDA-MB-231; adherens junction; breast cancer; mitochondrial membrane potential; tumor microenvironment.